With the increase in transmission speed from wireless base station apparatuses to switching systems, an optical transmission method has been used for cell phones and wireless systems. Since, in general, a wireless base station apparatus is installed outdoors, a connector portion of an optical cable connected to the apparatus needs to be waterproof. In some cases, in order to change a connector portion into a dedicated waterproof connector, a conversion cable is employed. However, since such a conversion cable is costly, a technique for directly making a connection portion between an optical module of an apparatus and an optical connector connected to the optical module waterproof is described below.
FIGS. 1A to 1D illustrate an example of an optical connector and an optical module widely used for optical transmission. FIG. 1A is a side view of the optical connector and the optical module. FIG. 1B is a top view of the optical connector and the optical module. As illustrated in FIG. 1A, an optical connector 1 is provided at the top end of an optical cable 5 in order to connect the optical cable 5 to an optical module 50 of an apparatus. As a general-purpose optical connector, an LC optical connector having a specification defined by the IEC61754-20 standard is widely used. A latch 2 having a protruding portion 6 in the middle of the upper surface thereof and a trigger lever 3 used to release the latch 2 by pressing the latch 2 are provided in the middle of the LC optical connector 1. The latch 2 and the trigger lever 3 are made of resin. The latch 2 and the trigger lever 3 are flexible. Even when the trigger lever 3 is being pressed and, thus, the latch 2 is also being pressed, the trigger lever 3 and the latch 2 return to their original shapes after the trigger lever 3 is released.
A jack 51 used for connecting the LC optical connector 1 is formed at the top end of the optical module 50. As illustrated in FIG. 1B, an opening 52 is formed in the top surface of the optical module 50. FIG. 1C is a side view of the LC optical connector 1 connected to the optical module 50. FIG. 1D is a top view of the LC optical connector 1 connected to the optical module 50. When the LC optical connector 1 is plugged into the optical module 50, the latch 2 is temporarily pressed towards the body of the LC optical connector 1 by a protruding portion 6 in the jack 51. Subsequently, if the LC optical connector 1 is further plugged into the optical module 50, the protruding portion 6 of the latch 2 reaches the position of the opening 52 formed in the upper surface of the optical module 50. At that time, the pressure that is applied to the protruding portion 6 disappears. Accordingly, the latch 2 returns to its original shape. Therefore, the protruding portion 6 of the latch 2 protrudes through the opening 52. At that time, since the protruding portion 6 of the latch 2 protrudes through the opening 52 and is caught on the edge of the opening 52, the LC optical connector 1 may not be removed from the optical module 50. In order to remove the LC optical connector 1 from the optical module 50, the trigger lever 3 has to be pressed. By doing so, the latch 2 is pressed downward, and the protruding portion 6 caught by the opening 52 is released.
FIG. 2A illustrates the LC optical connector 1 with a waterproof cover 30. A portion of the LC optical connector 1 to which the optical cable 5 is attached is made waterproof by using a housing 10. Furthermore, the housing 10 is made waterproof by using the waterproof cover 30. Thus, the connecting portion of the optical connector 1 with the apparatus is made waterproof. FIG. 2B illustrates the LC optical connector 1 with a waterproof cover illustrated in FIG. 2A connected to the optical module 50 of the apparatus with a waterproof cover.
By fitting a waterproof cover 40 provided on the outer side of the apparatus so as to surround the optical module 50 with the waterproof cover 30 provided on the optical module side, the connection portion between the optical module 50 and the LC optical connector 1 is completely covered and, therefore, is made waterproof. However, after the LC optical connector 1 with the waterproof cover 30 has been connected to the apparatus, the optical cable may not be removed in order to maintain or repair a board of the apparatus. That is, since the latch 2 and the trigger lever 3 are completely covered by the waterproof cover 30, the latch may not be released. Therefore, in the case where a waterproof cover is attached, a general-purpose LC connector needs to be configured so that a latch and a trigger lever are removable by scraping, or an LC connector without a latch needs to be prepared.
The followings are reference documents.    [Document 1] Japanese Laid-open Patent Publication No. 04-208904.